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Intrinsically Safe Test Tools and Standards North American rating Division 1 Division 2 European ATEx Zone 0 Zone 1 Zone 2 Gas Presence 1000 hours/year >10 hours,< 1000 hours/year > 1 hour, < 10 hours/year Certification Fluke products Main application 707Ex Loop Calibrator Source and measure mA signals All Gases 718Ex Pressure Calibrator Calibrate pressure transmittters and switches All Gases 725Ex Multifunction Calibrator Calibrate almost any process device Gases (North American gas groups B,C,D) (ATEx gas groups IIB) 87V-Ex Industrial Ex Multimeter True-rms IEC-1010 CAT IV 600 V rating All Gases C How do you know if the combination of test tool and device under test is safe? Visit www.fluke.com/ex and order a free intrinsically safe training CD Application Note Pressure switches are used in a wide variety of monitoring and control applications, such as HVAC air provers, defrost sen- sors, filter indicator applications, oil/hydraulic filter alerts and process break detectors. A pressure switch is triggered by changes in pressure within a system, which can be measured as pressure, vacuum, or differen- tial between two pressure inputs. In every case, the pressure switch will employ a diaphragm, piston, or other pressure-responsive sensor coupled to a switch actuating mechanism. In its most basic form, a pres- sure switch can monitor air flow in a heating system or control gas pressure in a water heater, acting as the watchdog in many process monitoring applications. Accurate calibration of pres- sure switches is a critical step in ensuring process quality and the safe operation of equipment. But even the most savvy process technician may not fully under- stand the correct method of cali- brating pressure switches. Fortunately, the best tool for the job is one many process techni- cians already own: a document- ing process calibrator, like the Fluke 740 Series. Documenting process calibra- tors (DPCs) are multifunction process tools that eliminate the need for technicians to carry multiple tools with them. “The 744 Documenting Process Cali- brator has literally saved me a zillion steps,” said Gene Guidry, Chevron Chemical, U.S.A. “I was carrying two, three, maybe even four pieces of test equipment plus my hand tools. Now I just take the 744, which incorporates calibration and HART communi- cation capability in a single, fast unit.” Calibrating a pressure switch using a DPC can be conducted manually or as an embedded task using DPC software. It also requires certain pressure acces- sories, including a pressure mod- ule and hand pump. The steps outlined below are specific to the Fluke 740 Series, but the process can be applied to virtually any DPC. Calibrating pressure limit switches The first step in the process is to set up the DPC. (Note: A number of the terms in this article apply to both temperature and pressure limit switch calibration and maintenance.) The DPC test setup screens prompt the user for the following information: • Setpoint: Main point at which the switch is supposed to take action. • Setpoint type: Can be “high” or “low.” This is the basic call to action. “Low” means that the action should happen when the process variable (PV) is below the setpoint. “High” means that the action should happen if the PV is above the setpoint. • Set state: State of the switch (set or reset) at the time the action takes place. • Tolerance: The allowable deviation from the setpoint. • Deadband min: Minimum value or size of the deadband. • Deadband max: Maximum value or size of the deadband. (note: the deadband of a pres- sure switch is the measured difference in the applied pres- sure when the switch is changed from set to reset) Calibrating pressure switches with a DPC • Trip function: This can be set for continuity, V ac or V dc, and refers to what is being measured as the setpoint is exercised by the simulated process variable. For example, suppose you want to control the pressure in a vessel set at 12 psi. You don’t want the relief valve to be open- ing and closing constantly, you want it to open at 12 psi and close again at approximately 10 psi, (12 psi - 10 psi = an approximate deadband of 2 psi). From the Fluke Digital Library @ www.fluke.com/library as tial b etween t In every case, the pressur w ill employ a diaphragm, piston, or other pressure-responsive sensor coupled to a switch actuating mechanism. In its most basic form, a pres- sure switch can monitor air flow in a heating system or control gas pressure in a water heater, acting as the watchdog in many process monitoring applications. Accurate calibration of pres- sure switches is a critical step in ensuring process quality and the safe operation of equipment. But even the most savvy process technician may not fully under- stand the correct method of cali- brating pressure switches. F ortunately, the best tool for the job is one many process techni- c ians already own: a document- ing process calibrator, like the Fluke 740 Series. D ocumenting process calibra- tors (DPCs) are multifunction process tools that eliminate the need for technicians to carry multiple tools with them. “The 7 44 Documenting Process Cali- brator has literally saved me a zillion steps,” said Gene Guidry, Chevron Chemical, U.S.A. “I was carrying two, three, maybe even four pieces of test equipment plus my hand tools. Now I just take the 744, which incorporates calibration and HART communi- cation capability in a single, fast unit.” lim The first step in the set up the DPC. (Note: A numb of the terms in this article apply to both temperature and pressure limit switch calibration and maintenance.) The DPC test setup screens prompt the user for the following information: • Setpoint: Main point at which the switch is supposed to take action. • Setpoint type: Can be “high” or “low.” This is the basic call to action. “Low” means that the action should happen when the process variable (PV) is below the setpoint. “High” means that the action should happen if the PV is above the setpoint. • Set state: State of the switch (set or reset) at the time the action takes place. • T olerance: T T The allowable deviation from the setpoint. • Deadband min: Minimum value or size of the deadband. • Deadband max: Maximum value or size of the deadband. (note: the deadband of a pres- sure switch is the measured difference in the applied pres- sure when the switch is changed from set to reset) • Trip function: This for continuity, V ac and refers to what measured as the s exercised by the s process variable. F or example, sup want to control the vessel set at 12 ps want the relief va ing and closing c want it to open close again at a 10 psi, (12 psi - approximate de From the Fluke Digital Library @ www.fluke. Application Note Tracking down problems within a process loop can be a difficult challenge in the best of environ- ments. Doing so in an area that has the potential for explosion takes the degree of difficulty to another level – one where the technician needs proper training and equipment. This article will demonstrate the practical applica- tion of loop calibrators designed to troubleshoot process loops in intrinsically safe environments. What is “intrinsically safe?” Intrinsic safety is a protection standard employed in potentially explosive atmospheres. Devices certified as “intrinsically safe” are designed to be unable to release sufficient energy, by either thermal or electrical means, to cause ignition of flammable material (gas, dust/ particulates). Intrinsically safe standards apply to all equipment that can create one or more of a range of defined potential explosion sources: • Electrical sparks • Electrical arcs • Flames • Hot surfaces • Static electricity • Electromagnetic radiation • Chemical reactions • Mechanical impact • Mechanical friction • Compression ignition • Acoustic energy • Ionizing radiation Intrinsic safety is particularly important for technicians working in industries like petro- chemical and pharmaceutical, around bulk materials such as grain, mining, or any environ- ment where explosive gases are present. The importance of safety in these environments can’t be stressed enough. It takes a very small amount of energy to cause an ignition; e.g., a mixture of hydrogen in air requires only 2O uJ of energy. The proper practices and tools will minimize the inherent risk involved in working around these hazards. Intrinsically safe loop calibration To conduct loop calibrations in potentially explosive environ- ments, you need a loop calibrator that is certified as intrinsically safe. Intrinsically safe loop cali- brators, such as the Fluke 707Ex, must be certified in accordance Troubleshooting process loops in potentially explosive atmospheres From the Fluke Digital Library @ www.fluke.com/library with the European ATEX (“Atmo- sphères Explosibles,” French for explosive atmospheres) directive (Ex II 2 G Eex ia IIC T4) in Zones 1 and 2 for use in Europe and NEC 500; N.I. Class 1, Division 2 areas Group A-D for use in the U.S. In addition to an intrinsically safe loop calibrator, strict adher- ence to calibration procedures is recommended, including: Lock out: Make sure the system is shut down and other workers are notified that a potentially dangerous operation will be tak- ing place. Tape off area: Tape the work area off to prevent workers from entering with potentially danger- ous electrical devices (cell phones, handheld computers, non-intrinsically safe tools). Purge or vent the systems: Safely purge or vent the system to remove any gases that may remain. Use a gas detector: In an envi- ronment where explosive gas may be present, the use of a gas detector is a prudent step before starting a loop calibration. Gas “sniffers” are available for a wide variety of applications and from handheld to larger, carted models. Calibrate: Perform your calibra- tion using an intrinsically safe loop calibrator. Clean up and reactivate: At the conclusion of calibration, reverse the process and reactivate the system. Loop calibration The 707Ex Loop Calibrator has the ability to replace the power source in a current loop so you can power and read a transmitter at the same time without carry- ing a digital multimeter (DMM). 石油化学製品のプラントは、甘えの許されない厳しい側面を持つ現場の1つです。法規で定められ た計測管理、設備の定期保全、機器の日常点検など、いずれの場面でも、安全で安定した操業を損な わない、高品質でコスト効率の高い校正機器が求められます。 フルークと、フルーク・キャリブレーションは、電気計測から、マルチファンクション・メーター、 mAループ、温度計測、圧力、流量にわたる領域で、皆様が日々直面する課題に合った、すぐれた プロセス校正ソリューションを用意しています。 石油化学産業における 校正ソリューション 石油化学産業で活躍するソリューション さらに広がる石油化学産業向けソリューション 特徴 • デジタル・マルチメーター とループ校正器が、1体に なったツールによる、電流 ループの校正とトラブル シューティング • 正確な温度測定 • プロセス計装機器の保全と 校正 • あらゆるプロセス変数の標 準信号出力、測定、ドキュ メンティング 石油化学産業での適用例 DCループ電流の測定、標 準信号出力、シミュレーショ ン出力。高精度の品質管理、 取引用計量。 圧力・温度トランスミッ ターの校正、HART機器の設 定と校正のほか、フィールド 校正の結果をドキュメント記 録して、校正管理ソフトウェ アへアップロードできます。 特徴 • 圧力ゲージ、圧力スイッチ、 トランスミッターの校正 • 採油現場の坑内圧力計器の 試験 • 圧力発生器とmA測定によ る、ほぼあらゆる圧力機器 にわたる保守 • 圧力と電流の同時測定によ る、P/I計器の校正 石油化学産業での適用例 内蔵センサーを使った圧力 測定。圧力発生と同時のmA 測定。高精度の手動/自動圧 力調節。 僻遠地の原油採掘、試掘な どでも活躍。 特徴 • 温度計の校正とトラブル シューティング • 温度センサーとトランス ミッターの試験 • 熱電対、RTDなどの電圧 値、抵抗値の測定、標準信 号出力 石油化学産業での適用例 熱電対、RTDなどの電圧 値、抵抗値の標準信号/シミュ レーション出力を使いながら の、熱電対、抵抗、電圧の測 定による、センサーとトラン スミッターの試験。信号の自 動ステップ/ランプ変化によ るリモート試験。ループ電力 の供給と同時のmA測定によ る、トランスミッターの試験。 リニアTCトランスミッター の校正。放射温度計や熱画像 機器の校正など。 特徴 • ループ結線のまま 4-20 mA信号測定 • mA信号の測定、標準信号 出力、シミュレーション • DC電圧の測定、標準信号 出力 石油化学産業での適用例 mA信号の測定、標準信号 出力、シミュレーション。ルー プの校正、保全、修理など。 特徴 • 質量流量計、 コントローラーの校正 • ロトメーターの校正 石油化学産業での適用例 パイロット設備でのプロセス 開発用、補助機器としてなど。 さらに詳しい内容は 石油化学分野向けの応用、事例、 ポスターなどを、インターネット でもご案内しています。 www.flukecal.jp 特徴 • 重要な用途に使われるHARTスマート計装機器の、稼働状況の ドキュメンティング • HART対応の温度・圧力トランスミッターのトリム調整 • HART機器のmA出力のトリム調整 • HART機器のLRV、URVによるレンジ変更 • HART機器の設定確認 • トランスミッターのmA出力を一定値に設定 • mA計測値の推移記録 • mA信号のほか、PV、SV、TC、QVを併せた推移記録 • タグ番号の設定と温度センサーのセットアップ 石油化学産業での適用例 HARTスマート・トランスミッターの校正、試験、トラブル シューティングのための、HART対応機器を取りそろえていま す。Fluke 754モデルでは、HART計器の校正結果をドキュメ ント記録し、Fluke DPCTRACK2などの、校正管理ソフトウェ ア（CMS; Calibration Management Software） に、 後 か ら送り渡せます。Fluke 709Hでは、HARTスマート機器の性能 を引き出すうえで必要な、ループの試験やトラブルシューティン グを、すべて実施できます。754では、そのほかにも、トランス ミッター入力信号のシミュレーションや、標準信号出力ができ、 トランスミッター全体の調整が行えます。 特徴 • 流体の接触温度計測 • 校正用バスや試験ウエルの 接触温度測定による、コン トローラーや、ゲージ、機 器表示の比較チェック • 外部の参照温度計を使った 校正確度の向上 • 温度推移の記録 石油化学産業での適用例 温度計器のチェックや校正 において、より高精度な参照 温度を提供するほか、温度の 簡単な正確測定によって、ほ かの計器の誤差を確認できま す。本質安全構造の1551 Ex 型は、防爆環境にも対応。 特徴 • 圧力ゲージ、圧力スイッチ、 トランスミッターの校正 • 圧力発生器とmA測定によ る、ほぼあらゆる圧力機器 にわたる保守 • 圧力と電流の同時測定によ る、P/I計器の校正 石油化学産業での適用例 内蔵センサーを使った圧力 測定。圧力発生と同時のmA 測定。高精度の手動/自動圧 力調節。圧力容器の安全確保 など。 特徴 • 指示温度計の校正 • RTD、熱電対の校正 • RTD、 熱電対の校正チェック • 温度コントローラーの ループ校正 • 温度トランスミッターと センサーの組み合わせ校正 • 温度スイッチの試験 石油化学産業での適用例 温度計器を正確な標準温度 と比較する、安定した参照温 度を提供し、被験機器の誤差 を検出して補正。 マルチファンクション 校正器 圧力校正器 温度校正器 校正用バス、ドライウエル 高精度温度計、温度プローブ デッドウェイト・テスター、 圧力コントローラー校正器 mAプロセス・ クランプメーター ガス流量校正器 HARTスマート計器校正器 Fluke Calibration.Precision, performance, confidence. ™ フルーク・キャリブレーション 〒108-6106 東京都港区港南2-15-2 品川インターシティB棟6F TEL 03-6714-3114／FAX 03-6714-3115 大阪営業所 〒532-0003 大阪府大阪市淀川区宮原4-1-6 アクロス新大阪 TEL 06-6398-5144／FAX 06-6398-5145 サービスセンター 〒259-0132 神奈川県中郡二宮町緑が丘1-14-1 TEL 0463-70-5603／FAX 0463-70-5604 www.flukecal.jp ©2015 Fluke Calibration. 仕様は予告なく変更される場合があります。フルーク・キャリブレーションの書面による許可 なく、この文書の内容を改変することはできません。 Printed in Japan. 2015/03_T 42645552A Pub-ID 12021-eng
